fix: update link to cron creation (#13876)

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sentry.io/crons/create/ -> sentry.io/issues/alerts/new/crons/

sentry.io/crons/create/ takes me to a page that seems to not exist, but
I found (i think) the right think in
https://sentry.io/issues/alerts/new/crons/

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Author: JacobCoffee

docs/product/crons/getting-started/http/index.mdx

@@ -10,7 +10,7 @@ Sentry Crons allows you to monitor the uptime and performance of any scheduled,
 
 To begin monitoring your recurring, scheduled job:
 
-1. [Create a new monitor](https://sentry.io/crons/create/) in Sentry.
+1. [Create a new monitor](https://sentry.io/issues/alerts/new/crons/) in Sentry.
 2. Configure check-ins or a heartbeat for your job.
 
 Optionally, you can skip the first step and [create or update (upsert) a monitor through a check-in](#creating-or-updating-a-monitor-through-a-check-in-optional). See more below.